Glossary


Streaming Media Glossary

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A-C

ADSL - (asymmetric digital subscriber line) Technology to carry high-speed data over ordinary phone lines. It is up to 70 times as fast as a 28.8 modem, and can be used concurrently with voice over the same line. It is called "asymmetric" because download speeds to the subscriber are faster than upload speeds from the subscriber.

AIFF - (Audio Interchange File Format) A file format that is used to store high-quality sampled audio and musical instrument (MIDI) information. AIFF files are similar to WAV files in both size and quality. Though AIFF files were originally created by Apple, audio programs on both the Mac and PC can usually read them.

API - (application program interface) An interface between the operating system and application programs that specifies how the two communicate with each other.

Applet - An application that is downloaded from a Web page and executed by browser software. Also, an HTML tag that defines an applet program.

Archive - A stroage repository for software, data, or other materials to be saved and preserved.

ASF - (Advanced Systems Format) An audio or video file encoded for use with Windows Media® Player.

Aspect ratio - The relationship of the height and width of a video on a monitor. Example: letterbox format is 16:9.

ATM - (Asynchronous Transfer Mode) A packet switching model for fast long distance communications that uses fixed packet size and allows for intelligent decisions on routing, handling, prioritization, and costing. This allows for special handling and routing for data that must be reassembled quickly and accurately, such as live video.

Audio directory - Directory with specific settings to encode WAV or MP3 to Windows Media® 4.1 audio files.

AVI - (Audio Video Interleave) A Microsoft video format containing multiple streams of different types of data, such as audio and video. AVI files will end with an .avi extension.

Backbone - A central network connecting other networks together.

Bandwidth - In digital terms, the capacity of a connection to transmit data expressed as data speed in bits per second (bps) thousands of bits per second (Kbps), or millions of bits per second (mbps).

Bit rate - The speed at which binary content is streamed on a network, measured in kilobits per second (kbps). It takes 8 bits to make up 1 byte which is the size of one letter, number or symbol.

BNC, BNC connector - (Bayonet connector or Baby N Connector or Bayonet Neill-Concelman) A twist-and-lock connector for coaxial cable, BNC connectors are used for electronic equipment and LANs and permit frequencies into the gigaHertz ranges.

Bps - Bytes per second.

bps - Bits per second.

Broadband - Describes a high-speed network connection (T-1, DSL, cable modem) as opposed to a dial-up connection.

Buffering - Buffering is similar to the concept of "pre-filling." The stream of data begins before the media file actually plays. This data goes to local storage so that the incoming data always stays ahead of the actual data being viewed. Occasionally, if there is significant network congestion, a media file may stop playing momentarily so that the buffer can be refilled.

Cache - A place to store something temporarily so it can be accessed quickly. Web pages that are viewed are generally stored temporarily on the user's hard drive, for quick access on return visits. Caching can also refer to distributing Internet content to multiple servers that are periodically refreshed.

Capture - The process of changing or transferring digital or analog audio or video files to binary files, which can then be edited and encoded.

CDN - (Content Delivery Network) A system of computers containing copies of data, placed at various points in a network so as to maximize bandwidth for access to the data from clients throughout the network.

CGI - (Common Gateway Interface) A memthod used by WWW pages to communicate with programs run on the Web server.

CIF - (Common Intermediate Format) A standard video format used in video conferencing. Define CIF formats by their resolution, and standards both above and below the original resolution established. The original CIF is also known as Full CIF (FCIF). A frame size of 352 x 288 (width x width in pixels) for PAL (European Standard). A frame size of 320 x 240 (width x width in pixels) for NTSC (U.S. Standard).

CODEC - (compress/decompress)A media file is encoded or compressed using an algorithm or formula and then decoded and decompressed as the user views or listens to the file.

Compression - It is desirable to compress media files to reduce file size and speed up the transmission time. This can be done using hardware, software, or a combination of both. Compressed media files are then decompressed on the user's end.

CRC - (cyclic redundancy check) A technique of providing a data string added to packets of information that can be used to detect errors in the data packets.

D-F

Data rate - The number of kilobits per second requried to replay the compressed video at the intended frame rate and quality.

DCOM - (Distributed Component Object Model) A proprietary Microsoft technology for communication among software components distributed across network computers.

Deblocking Filter - Optional block edge filter within the coding loop. It reduces the appearance of block like artifacts that appear in highly compressed video streams. Use during capture for real-time processing and during conversion or playback to enhance existing media files.

Default directory - The directory from which files are typically opened and stored.

Delay buffer - A memory storage area to accumulates video data for the compressor and ensure adequate data availability.

Destination directory - The target directory when moving data.

DHCP - (Dynamic Host Configuration Protocol) a protocol network devices (clients) use to obtainthe parameters necessary for operation in an Internet protocol (IP) network. It reduces system administration workload by allowing users to add devices to the network with little or no manual configuration.

Digital Rights Management - Hardware manufacturers, publishers, and copyright holders use this as an access control technology to limituse of digital media or devices.

Digital video - – An alternative way of storing or distributing video. Digital video is usually converted from an analog video source.

DNS - (domain name system) DNS servers are located at many strategic places on the nets to resolve the routing of e-mail and Internet connections. No single DNS server has all the address information of the Internet, and successful routing may require routing through several levels of servers.

Download - To transfer a file from another system to your own computer system via a modem over telephone or cable lines or a telco connection using a transfer protocol. Less precisely, it may also refer to a direct transfer from a server to your local terminal over a local area network or an FTP transfer from a remote system to your system.

DRM - (digital rights management) A generic term for access control technologies that can be used by hardware manufacturers, publishers, copyright holders and individuals who try to impose limitations on the usage of digital content and devices.

DSP - (digital signal processor) A chip optimized to perform repetitive mathematical calculations, such as encoding and decoding.

Encode - To format (electronic data) according to a standard format.

Encoder - A hardware device or software that changes a signal (such as a bitstream) or data into a code. The code may perform such actions as compressing information for transmission or storage, encrypting or adding redundancies to the input code, and translating from one code to another. Examples include: compressing audio/video into a smaller form; multiplexing to combine inputs into one output; functioning as a rotary encoder to convert rotary position to an analog electronic signal; and functioning as a linear encoder to convert linear positions to electronic signals.

Encoding options - The number of speeds, file formats, and other settings available for encoding.

Flash® - A vector based animation format released by Macromedia now owned by Adobe® often used for narrative productions on the Web.

Formats - The arrangement of data for storage or display. A method for achieving such an arrangement.

FPS - (frames per second) A media stream containing multiple streams of different types of data, such as audio, video, or MIDI. The number of video frames displayed each second. Generally, the higher the number, the smoother and sharper the images appear.

FTP - (File Transfer Protocol) The Internet protocol that permits you to transfer files between your system and another system.

Frame rate - The number of frames of video displayed during a given time – usually measured in seconds.

Frame size - The pixel width and height of video image.

G-L

Gbit- Gigabit

GB - Gigabyte

HD-SDI - (high-definition serial digital interface)

Hosting - Storing media files on servers specifically designed for streaming over the Internet.

HTML - (HyperText Markup Language) The coding system used to create WWW pages. A page written in HTML is a text file that includes tags in angle brackets that control the fonts and type sizes, insertion of graphics, layout of tables and frames, paragraphing, calls to short runable programs, and hypertext links to other pages. Files written in HTML generally use an .html or .htm extension.

http - (Hyper Text Transfer Protocol) It is the main protocol used on the Internet that enables linking to other Web sites. Addressing to other Web pages begins with "http://" and is followed by the domain name or IP address.

Hyperlink - A link in a Web page that brings you to another location or resource when activated. Hyperlinks usually appear as underlined text and printed in a contrasting color, but they may also appear as graphics, such as buttons to click. Hyperlinks may link to another place in the same page, to a different page, to play an audio or video file, to download a file, to set up a message to an e-mail address, to search a database, to read Usenet newsgroups, and to link to other Internet resources.

IP - (Internet Protocol) The network layer for the TCP/IP protocol suite widely used on Ethernet networks, defined in STD 5, RFC 791. IP is a connectionless, best-effort packet switching protocol. It provides packet routing, fragmentation and re-assembly through the data link layer.

ISDN - (Integrated Services Digital Network.) A technology that carries data over phone lines at up to 128Kbps for dialup users, but extends to fast broadband communications, too. It applies to the first three layers of the OSI and TCP/IP models.

kbps - (kilobits per second) The rate at which data is sent over a communication line.

Key frame - A full frame of compressed video that the decoder uses as a reference frame of video for subsequent delta frames.

Lossy compression - Data compression by eliminating perceptually insignificant information. However, since lossy compression introduces inaccuracies, it should only be used with graphics, audio, and video. Data files and executable programs can only be compressed with a lossless algorithm (i.e., a zip file).

M-Q

M2TS - (MPEG-2 transport system) A container file format for multiplexing audio, video and other streams. This format is commonly used for high-definition video on Blu-ray Disc and AVCHD.

MAC - (Media Access Control) A unique identifier assigned to most network adapters or network interface cards (NICs) by the manufacturer for identification.

mbps - (millions of bits per second) A measure of bandwidth. A unit of information transfer rate.

Metadata - Additional, related information that can be stored as part of the compressed file or kept in a separate database. Examples include CD cover art, movie one-sheet images, or text-based information, such as author, title, etc.

Metafile - A graphics format that combines the features of bitmap and vector graphics. Common types of metafile formats are CGM, Corel Draw CDR files, encapsulated Postscript EPS files, Adobe Illustrator, Word Perfect Graphics WPG files, PICT, and RTF.

MP3 - A digital audio compression algorithm that achieves a compression factor of about 12 while preserving sound quality MP3 is an algorithm in a series of audio encoding standards develped under the sponsorship of the Moving Picture Experts Group (MPEG) and formalized by the International Organization for Standardization (ISO).

MPEG - Moving Pictures Experts Group

MPEG-4 - A compression/decompression technology that aims to achieve interactivity, efficiency and stability in narrowband transmissions. MPEG-4 is designed for low bit rate communications devices, such as mobile receivers that can display video.

Multicast - Applies when sending a piece of information from one or more points to a set of other points.

NAP - (Network Access Point) A point where networks and service providers hand off traffic to each other. NAPs are typically the points with the worst congestion problems.

Narrowband - Describes a connection over a computer network which supports a relatively low bit rate.

Narrowcast - Used to send data to a specific list of recipients.

Net Congestion - Traffic on the network that slows the transmission of data.

Niagara encoders - ViewCast Niagara streaming media encoders deliver the quality, features and ease-of-use convenience that professional broadcasters demand. These pre-configured, plug-and-play solutions enable users to quickly capture and broadcast premium quality audio and video in mulitple formats and at multiple bit rates - all simultaneously.

Niagara SCX - A streaming media management software that installs on a user-encoding device connected with remote SCX Explorer workstations. It too allows users to manage live video broadcasting over the Internet and to mobile devices from their remote workstations. It coordinates the streaming process to allow users to set up and control Niagara streaming systems positioned throughout their enterprise or anywhere in the world - all from the desktops. It functions as one part ot the total encoding solution to allow users utimately to control and monitor each individual stream.

Niagara SCX Explorer - A streaming media management software that installs on any user client device. It lets users manage live video broadcasting over the Internet and to mobile devices. It lets users set up and control Niagara streaming systems positioned throughout their enterprise or anywhere in theworld - all from their desktops tat interface to the server. Users can instantly see: the status of all of their networked encoders and which encoders have active encode sessions. It allows users to navigate through the application to control and monitor each individual stream. It can interface with the SCX Explorer Manager to become part of the total encoding operation.

NIC - (Network Interface Card) For example, an Ethernet card in a network.

Noise Reduction - A variety of processes applied to audio or video signals to lower the amount of noise in the given signal.

NTSC - Input signal formats used in North America and Japan. Has 525 lines total with 480 lines visible per frame.

OEM - (original equipment manufacturer)

Packet - A packet is a self-contained bundle of data sent over a packet switching network. Packets are typically less than 1500 bytes in size. Longer files are broken into multiple packets for transmission and reassembled at the other end. A packet includes a header with to and from addresses, relation to other packets (sequencing), and error checking information.

Packet Loss - Data is transmitted in small units known as packets. Occasionally, packets are lost or delayed due to network congestion, resulting in dropped frames.

PAL - Input signal format used in Europe, Brazil, Argentina, Paraguay and Uruguay. Has 625 lines total, 576 lines visible.

PCI - (Peripheral Component Interconnect) An industry-standard bus for attaching peripherals to computers using a shared parallel bus.

PCIe - (Peripheral Component Interconnect Express) An industry standard computer expansion card interconnect that uses a point-to-point serial link.

Pixel - Digital images are composed of any array of individual dots called picture elements, or pixels.

Port - A connection to a computer to enable other devices, such as printers, modems, monitors, keyboards, mice, and so on. to interface with the computer. A logical connection to a network.

Pre-Processing - Applying filter or mathematical operations to video prior to compression. The process may include PC interlacing, cropping, scaling, Inverse Telecine, and color correction.

Protocol - A uniform set of rules that enable computers to connect to one another. Protocols determine how data is transmitted between computing devices and over networks.

QuickTime - Multimedia architecture used by software tool vendors and content creators to store, edit and play synchronized graphics, sound, video, and music.

R-Z

RJ-11 - The type of modular jack used with telephones. It connects one to three pairs of wires with a connector that plugs into your phone on one end and a wall jack on the other.

RJ-45 - A modular jack that can connect up to four pairs of wires. It resembles the RJ-11 telephone jack, but is a bit larger. It is commonly used to connect twisted pairs of cable in a LAN.

RealAudio - A file format for audio only streaming media technology released by RealNetworks.

RealFlash - A Flash presentation synchronized with a RealAudio soundtrack, playable in RealNetworks client software.

RealMedia - File formats, server software, player software, and protocols used by streaming media systems from RealNetworks.

Real-time video - Video from a video source, such as a camera, that the compressor then processes immediately and sends for decompression and playback.

Router - A router connects networks together, controlling the routing of packets from source to destination and providing alternate paths when necessary. Routers are more sophisticated than bridges, connecting networks of different types, with the ability to make logical routing decisions on the basis of available data.

RTMP - (Real Time Messaging Protocol) A proprietary protocol developed by Adobe Systems for streaming audio, video, and data over the Internet, between a Flash player and a server.

SAN - (storage area network) A high speed network of shared storage devices.

SDK - (software development kit) Typically a set of development tools that allows a software engineer to create applications for a certain software package, software framework, hardware platform, computer system, video game console, operating system, or similar platform

SDI - (serial digital interface) Refers to a family of video interfaces standardized by SMPTE.

SECAM - (Sequential Color with Memory) An analog color television system first used in France.

Server - A computer in a network that provides access to other computers in the network to programs, web pages, data, or other files and services, such as printer access or communications access. A server may also authenticate requests for files and services before providing them.

SMPTE - (Society of Motion Picture and Television Engineers) An internationally recognized standards developing organization.

Source directory - The origin directory of a file.

Source material - The data, video or audio content to be encoded.

Speeds - The rate of bandwidth when sending or delivering data.

SECAM - Input signal format used in France and a few other countries. Has 625 lines total, 576 lines visible.

SQL - (structured query language) Used to manipulate data from a relational database.

Standard-definition resolution - The display resolution of a digital television or display device as referenced to the same resolution as analog systems.

Streaming audio and video - Streaming allows the user to watch or listen to a media file without downloading it. The file is simultaneously "streamed" to the user as he or she is watching or listening to it. The user needs a player to view or listen to the files - files must be decompressed by a media player that is compatible with the format of the file.

S-Video - Y/C analog video signal; carries video data as two separate signals – no audio.

T-1 - A digital communications circuit that transmits at 1.54 Mbps. (equals approximately fifty-three 28.8k modems)

T-3 - A digital communications circuit that transmits at 45 Mbps. (equals approximately 1,548 28.8k modems)

TCP - (Transmission Control Protocol) Standard protocol designed for transmitting text and ASCII data across the Internet and other IP-based networks.

Transcoding - The conversion of one digital file format to another digital file format (i.e., MP3 to Windows Media). The ideal method for encoding to multiple streaming media formats is to use the original, uncompressed source material and encode it into the new formats, avoiding transcoding completely.)

Unicast - Unicast communication applies to a piece of information that users send from one point to another point.

Upload - To transfer a file from your computer system to another system via a modem over telephone or cable lines or a telco connection using a transfer protocol. A transfer from your system to a remote system.

Video Device - Any device capable of outputting video, Example: camera, VCR, DVD, CD-ROM.

VOD - (Video on Demand): Video that can be accessed at any time by the user.

WAP - (wireless application protocol) A protocol that defines delivery and access of information to WAP-enabled wireless devices.

WAV - A sound format developed by Microsoft and used extensively in Microsoft Windows.

WDM - Windows driver model

WMA - (Windows Media Audio) An audio compression format developed by Microsoft.

WMV - (Windows Media Video) A video compression format developed by Microsoft.

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